.

Author: hughsk

.gitignore

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+node_modules

index.js

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+const postcss = require('postcss')
+
+module.exports = postcss.plugin('postcss-prefix', postcssPrefix)
+
+function postcssPrefix (prefix, options) {
+  options = options || {}
+
+  return function (root) {
+    root.walkRules(function (rule) {
+      if (rule.selector === ':root') return
+      rule.selector = prefix + rule.selector
+    })
+  }
+}

package.json

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+{
+  "name": "postcss-prefix",
+  "version": "1.0.0",
+  "dependencies": {
+    "postcss": "^5.0.8"
+  },
+  "devDependencies": {
+    "tape": "^4.2.1"
+  }
+}

test/fixture-out.css

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+:root {
+  --color-red: #f00;
+  --color-blue: #00f;
+}
+
+#hello-world h1 {}
+#hello-world h1.title {}
+#hello-world h2#thing {}
+#hello-world #thing h3 {}
+
+@media screen and (max-width: 42rem) {
+  #hello-world #another .thing > x-here {}
+}

test/fixture.css

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+:root {
+  --color-red: #f00;
+  --color-blue: #00f;
+}
+
+h1 {}
+h1.title {}
+h2#thing {}
+#thing h3 {}
+
+@media screen and (max-width: 42rem) {
+  #another .thing > x-here {}
+}

test/index.js

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+const prefix = require('../')
+const postcss = require('postcss')
+const test = require('tape')
+const path = require('path')
+const fs = require('fs')
+
+test('postcss-prefix', function (t) {
+  const expected = fs.readFileSync(path.join(__dirname, 'fixture-out.css'), 'utf8')
+  const css = fs.readFileSync(path.join(__dirname, 'fixture.css'), 'utf8')
+  const out = postcss()
+    .use(prefix('#hello-world '))
+    .process(css)
+    .toString()
+
+  t.equal(expected, out, 'output is as expected')
+  t.end()
+})